Overview and Status ofAdvanced Interferometers

Hartmut Grote (AEI Hannover and LIGO Lab)On behalf of the LIGO scientific collaborationLIGO doc. Nr. G1501194

TAUP, Torino11.Sept. 2015

Gravitational Waves

Distortion of space-time traveling at the speed of light

Gravitational Waves

Distortion of space-time traveling at the speed of light

...traveling at the speed of thought !!

A.S.Eddington

The Gravitational-wave Spectrum

01010101010

3-3-8-16Hz

Ground-basedinterferometers

InterferometersIn space

Pulsar timingInflationprobe

Supernovae

Spinning NS

BH and NS binaries

Binarycoalescence

Supermassive BHbinariesPrimordial

GWs

Cosmic strings

h

VIRGO cluster

Binary NS coalescence

h

Virgo Cluster50 million light-years away(15Mpc)

NS Binary

Time

h L / L

hNS ~ 1022

Gravitational waves are hard to measure,they are small...

strain

Inspiral signalfrom NS binaryin Virgo cluster

7

The pioneer of the GW-detection research:

Resonant antennas: bars („Weber-bars“)

Joseph Weber (1919 – 2000)

Resonant Bar Detectors

M ~ a few tonsL ~ 3 mF ~ 900 Hz

AurigaLegnaro, INFN (Italy)

AllegroBaton Rouge, LSU (USA)

NautilusFrascati, INFN (Italy)

ExplorerGeneva, CERN, INFN (Switzerland)

NiobePerth, UWA (Australia)

Resonant Bar Detectors

M ~ a few tonsL ~ 3 mF ~ 900 Hz

AurigaLegnaro, INFN (Italy)

AllegroBaton Rouge, LSU (USA)

NautilusFrascati, INFN (Italy)

ExplorerGeneva, CERN, INFN (Switzerland)

NiobePerth, UWA (Australia)

STILL RUNNING !

h ~ 10 -21 @ ~900 Hz

RETIRED

Michelson Interferometers

Gravitational wave propagation

Michelson (with additions)

Michelson-Morley experiment:Accuracy: 10^-8 m (10^-9 relative)

Advanced Interferometer:Accuracy: 10^-19 m (3 x 10^-23 relative), 100Hz BW

10m arm-length 3-4 km arm-length

4 optical resonatorsarranged aroundMichelson IFO

Michelson (with additions)

Michelson-Morley experiment:Accuracy: 10^-8 m (10^-9 relative)

Advanced Interferometer:Accuracy: 10^-19 m (3 x 10^-23 relative), 100Hz BW

10m arm-length 3-4 km arm-length

Measurement limitedby Heisenberg uncertaintyh ~ dx * dp (40kg masses)

13

...and a bit closerTo reality...

14

Current GW – Interferometer Projects

LIGO Hanford KAGRA

VIRGO

GEO600

LIGO Livingston

4km

4km

3km600m

3km

92

LIGO Hanford

LIGO India ?4km

15

Current GW – Interferometer Projects

LIGO Hanford KAGRA

VIRGO

GEO600

LIGO Livingston

4km

4km

3km600m

3km

92

LIGO Hanford

LIGO India ?4km

2015

16

Current GW – Interferometer Projects

LIGO Hanford KAGRA

VIRGO

GEO600

LIGO Livingston

4km

4km

3km600m

3km

92

LIGO Hanford

LIGO India ?4km

2015

2016

17

Current GW – Interferometer Projects

LIGO Hanford KAGRA

VIRGO

GEO600

LIGO Livingston

4km

4km

3km600m

3km

92

LIGO Hanford

LIGO India ?4km

2015

2016

2017/18

Improving Sensitivity in Advanced Detectors

Initial

Advanced

Initial

Advanced

Detectionrange foraverageorientedBNS inspiral(SNR=8):

Initial: ~20Mpsec

Advanced:~200Mpsec

TECHNOLOGIES

Dominated by seismic noise Managed by suspending the

mirrors from extreme vibration isolators

– Virgo Superattenuator (from 1st generation) / 8 stages

– LIGO active system + 4 stages Technical noises of different

nature are the real challenge in this range

Ultimate limit for ground based detectors: gravity gradient noise

20

LOW FREQUENCY RANGE

Adv. Virgo Adv. LIGO

Dominated by thermal noise of – Mirror coatings– Suspensions

Reduced by:– Improved optical configuration: larger

beam spot – Mirror coatings engineered for low losses – Test masses suspended by fused silica

fibers (low mechanical losses)

21

MID FREQUENCY RANGETECHNOLOGIES

Dominated by laser shot noise Improved by increasing the power:

>100W input, ~1 MW in the cavities REQUIRES:

– New laser amplifiers (solid state, fiber)– Heavy, low absorption optics (substrates,

coatings)– Smart systems to correct for thermal

aberrations: Ring heaters, heat projectors, scanning CO2 lasers

22

HIGH FREQUENCY RANGE

TECHNOLOGIES

ADVANCED VIRGO

Advanced Virgo (AdV): upgrade of the Virgo interferometric detector of gravitational waves

Participated by scientists from Italy and France (former founders of Virgo), The Netherlands, Poland and Hungary

Funding approved in Dec 2009 (23.8 ME)

5 European countries19 labs, ~200 authors

APC Paris ARTEMIS NiceEGO CascinaINFN Firenze-UrbinoINFN GenovaINFN NapoliINFN PerugiaINFN PisaINFN Roma La SapienzaINFN Roma Tor VergataINFN Trento-PadovaLAL Orsay – ESPCI ParisLAPP AnnecyLKB ParisLMA LyonNIKHEF AmsterdamPOLGRAW(Poland)RADBOUD Uni. NijmegenRMKI Budapest

LVC, Budapest, Sep 2, 2015 G Losurdo - AdV Project Leader 24

Virgo INPUT TEST MASS PAYLOAD

25

FIRST “MINITOWER BENCH” (SIB2) INTEGRATED

Status of Advanced Virgo

● Installation in progress, to be completed end of 2015

● Plan to take observational data together with LIGO in 2016!

Advanced LIGOLIGO scientific collaboration:

17 countries,80+ institutions900+ members

Status of Advanced LIGO

● Installation (project) completed in March 2015● Both interferometers reached first stage

sensitivity (~60Mpsec)● First observational run (O1) of advanced

detector era to start Monday (14.Sept.2015) !

Can we expect GW detections ?

Observing prospects

KAGRA Project• Cryogenic and Underground Gravitational-

wave detector• Host: U of Tokyo ICRR• Co-host: NAOJ, KEK • ~230 collaborators from ~60 universities

Kamioka site

Entrance

KamLand(Neutrino)

Super-Kamiokande(Neutrino)

XMASS(dark matter)

CLIO(GW)

KAGRA Office

CRYOGENIC, UNDEGROUND interferometer

Cryostat Design

• 2.6 diameter, 3.6m high, 10 ton• 8K an 80K● 4 pulse tube cryo-coolers for each cryostat

20K

8K

80K

• Both 3 km arm vacuum tubes (800mm d) and 125 baffles were jointed and leak tested → no leak!

• Cryostats installed

Y arm X arm

photos by S Miyoki

Vacuum system

photo by N Kimura

Control Room

2012 2013 2014 2015 2016 2017 2018

Project Started in 20101 yr delay due tothe earthquake

• Simple 3-km Michelson ifo• Room temperature• Simplified suspensions

• Dual-recycled FP MI ifo• Cryogenic temperature• VIRGO-type big suspensions

iKAGRA bKAGRA

EngineeringObservation

FirstObservation

KAGRA timeline

GEO600

Smaller-scale detector run as prototype observatory.Development and test of new technologies.Example: Control and long-term application of squeezed light.

Squeezed light at GEO: 3.7 dBreduction of read-out noise

Beyond Advanced Interferometers

● Upgrades with squeezed light planned for LIGO and Virgo

● LIGO: likely suspension/mirror upgrade, perhaps new detector in same facility on intermediate timescale (10y). Perhaps new facility

● ET (europe): New facility, 10x more sensitive than advanced IFOs (design study completed)

Summary

● Gravitational waves as new tool for astronomy, just around the corner...

● Advanced Interferometers (Virgo, LIGO, KAGRA) progressing nicely, on schedule

● LIGO starting 1st observational run (O1) next week, Virgo to join O2 in 2016, KAGRA 2017/18

● Expect 1st detections within few years...

Limiting Noise

October 25, 2013 Katherine Dooley 45

Vacuum fluctuations in interferometers

Diagrams credit: L. Barsotti, K. Dooley

October 25, 2013 Katherine Dooley 46

Vacuum fluctuations in interferometers

Diagrams credit: L. Barsotti, K. Dooley

Squeezing the phase quadrature of the vacuum field entering the anti-symmetric port reduces the readout noise.

AURIGA & NAUTILUS continously on the air ~ 90% (combined)

with noise close to Gaussian (~ 20 outliers/day at SNR>6)until LIGO/Virgo resume operation

AURIGANAUTILUS

AUNA: “astrowatch” of AURIGA & NAUTILUS under triggersfrom SN neutrinos, giant X-rays flares, etc